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DMX-1000 Signal Processing Computer. Dean Wallraff, USA 1978

DMX-1000 Signal Processing Computer

The DMX-1000 was one of the earliest Digital Synthesisers. Essentially it was a dedicated 16 bit audio processing computer designed as an OEM product to be integrated into a existing computer setup – usually a DEC PDP11 microcomputer – where the user would write their own interface and score programmes to run the DMX 1000 from the master computer. The instrument sold for $XX in 1979 putting it beyond the reach of most musicians, however, the DMX was not intended as a mass market product but aimed at electronic and computer music studios (one of the first models being purchased by the University of Milan Cybernetics institute). The instrument was designed and built by Dean Wallraff previously a programmer at the M.I.T. Experimental Music Studio:

“…I worked there M.I.T.) as a Technical Instructor, mostly doing programming on one of the first visual score editors for music. I composed music using their system, always in non-standard tuning systems. It was slow work, since it took the computer half an hour of calculation to generate a minute’s worth of sound, which was then played back from disk. Some of my music was released on records.

After a year and a half, I decided it was time to leave. The work was getting repetitious, and the pay was low. The big problem was that I would miss the studio’s system, which was the only way I could make music in my non-standard tuning systems. I decided to build my own digital synthesizer, which would let me compose at home, and would generate sound in real time. We moved to New York at this time, into an apartment in an Italian section of Brooklyn…I worked my day job, developing funds-transfer systems for Chase and Citibank, and my night job, designing and building my synthesizer”

dmx-1000 running from a LS1 computer 1982

The DMX 1000 was capable of running a varied combination of oscillators, filters and noise generators which could be polyphonically combined and patched (a maximum of 20 simple oscillators with amplitude and frequency control reduced to 14 oscillators with envelope control, or alternatively 6 voices of frequency modulation, 15 first order filter sections, or 8 second order filter sections, or 30 white noise generators) . this made the machine as powerful as the most complex analogue synthesiser on the market at the time but with the additional benefit of being entirely programmable and run from a user generated score in real-time.

To avoid the complexity of the user having to integrate into an existing computer system and write their own software, a complete system,The DMX-1010 was later designed by Wallraff’s Digital Music Systems company which consisted of a LSI-11 based computer system running score and synthesis software with a floppy disk, CRT terminal, a 61-note keyboard.

DMX-100 and Pod-X

Pod-X was a collection of composition tools designed specifically for the DMX-1000 by the Candadian composer, Barry Truax in 1982 based on his ongoing Pod (POisson Distribution) probability composition model.

“PODX started in 1982 with the acquisition of the DMX-1000 (still working, amazingly enough) – which allowed the flip remark of the “X-rated POD system” to be occasionally uttered. Maybe I could just apply to the Guinness Book of Records for the longest continuously running (and used) computer music system, though it has seen several metamorphoses over that period. And possibly is one of the most productive…”

Despite the DMX-1000’s flexibility it was rapidly killed off by the advent of powerful and much more affordable digital synthesisers such as the Yamaha DX range of FM instruments.

“We sold dozens of the machines during the next few years, to university computer music studios and research organizations. It was the most flexible real-time synthesizer you could buy at the time, and it allowed composers to do things they couldn’t do with any other affordable system. But Yamaha introduced the DX-7 in the mid-80’s, which provided more raw synthesis power (though less flexibility in programming) in a unit that cost a tenth the price of ours. I spent a year or so trying unsuccessfully to raise money to develop a new generation of synthesizers, and then got out of the business.”